The present invention relates to a transmitter system for a Ferraris motion transmitter.
A typical transmitter system for a Ferraris motion transmitter includes one or more magnetic field generators which form together with an electrically conducting measuring body a magnetic measuring arrangement, whereby magnetic field generator(s) and the measuring body move relative to one another during operation. A magnetic field sensor is linked to the magnetic measuring arrangement to provide a speed-dependent or acceleration-dependent output signal. Such a transmitter system is disclosed, for example, in an article by A. Denne. H. Rausch and W, Freise, entitled “Aufnehmer zur Messung sctinell veränderlicher Drehbeschleunigungen und Drehmomente” [Measuring of dynamic angular acceleration and torque], and published in Technisches Messen 48, 1981, Number 10, page 339 to 342. Hereby, the measuring body is implemented as a rotating bell-shaped rotor.
German patent publication DE 37 30 841 A1 discloses a further transmitter system of this type in which the measuring body is implemented as disk.
Provision of a transmitter system of simple and compact structure is desirous because of cost-saving aspects and small outer dimensions to satisfy an increasing demand for miniaturization and to allow their use in volume-critical devices. Conventional transmitter systems have a mechanical play between measuring body and other components of the transmitter system that may result in measuring errors. In conjunction with a rotating measuring body, the mechanical play may result in a misalignment between the symmetry axis of the measuring body and the shaft and/or the measuring body is not entirely rotation-symmetric. Other errors may be caused, for example, through eccentricity, wobbling or inhomogeneities of the measuring body. To address this problem, it was proposed to use at least two magnetic field sensors which are evenly spaced about a circumference. This, however, resulted in a more complicated structure of the transmitter system.
It would therefore be desirable and advantageous to provide an improved transmitter system which obviates prior art shortcomings and is simple in structure while yet being reliable in operation and producing enhanced measuring quality.